1. Field of the Invention
The present invention relates to electronic devices including: information terminals such as stationary telephones, facsimiles, and personal computers; information terminals connected to the Internet and which transmit and receive information; and portable information terminals such as cellular telephones, PHS (personal handy phone system), and PDA (personal digital assistants). Note that, in this specification, the term portable information terminal indicates an electronic device which is capable of being carried by a user, and capable of sending and receiving data and information through a wireless telephone, a wire telephone, or the Internet, inside and outside of a structure.
2. Description of the Related Art
Information terminal electronic devices such as stationary telephones, facsimiles, and personal computers, and portable type electronic devices represented by typically portable telephone devices (referred to simply as cellular telephones), are spreading rapidly due to a combination of the establishment of information communication networks such as telephone lines, wireless communication lines, and the Internet, and the reduction in communication fees (or connection fees) and in price of electronic devices themselves, and the convenience. Electronic devices, spreading at present and functioning as information terminals and portable information terminals, are provided with a display device, a communication circuit, an MPU (microprocessor), a storage medium such as semiconductor memory, and input keys.
Portable electronic devices, typically cellular telephones, have come to be selected by users not only on their styling and function, but also on factors such as weight and length of continuous operation time. Various techniques for making the weight of portable electronic devices lighter and for lengthening time during which the electronic device can be used on a single charge, are therefore being concentrated upon. As a result, functionality thought to be unnecessary is being eliminated as much as possible.
Conventional communication lines, using stationary telephone devices, mainly for voice communication, often perform communication of a large amount of data containing image information due to the development of information communication networks as stated above, and due to the spread of information terminals. It is possible not only to send and receive data and electronic mail using personal computers, but also to send and receive electronic mail using portable telephone devices.
However, information terminals which are useful for the public such as stationary telephones and facsimiles, and portable electronic devices represented by typically portable telephone devices, are limited in their external design and external size, and thus functions thought to be unnecessary are eliminated as much as possible.
In electronic devices for which the portability is taken into account, such as portable telephone devices and PDAs, the number of input keys is normally about 12, corresponding to numerals and special keys. In order to input Japanese characters including Kanji and other special characters as data, it is necessary to perform complex operation with switching over input modes. It is therefore necessary to refer to an operation manual included with the electronic device, and the desired data cannot be smoothly input if the user forgets the method of operation.